Yes I suspected that these would not be SW issues
Coming back on the history of my setup, I realized that I had changed motherboard, migrating to a more recent Skylake core i5 6600K + Asus B150I Pro Gaming motherboard. My previous setup was an older core i5 + MSI motherboard.
It is complicated to revert to the old setup, so hard for me to confirm this is indeed the issue.
I should point out that I use a USB3 extender cable (from Amazon), because my PC is on the wrong side of the desktop. Could this cause issues ? Do you have a way to measure USB3 data transfert (since I know USB3 can be pretty finicky).
Regards
Vincent